Ultrarobust and Biomimetic Hierarchically Macroporous Ceramic Membrane for Oil–Water Separation Templated by Emulsion-Assisted Self-Assembly Method

Abstract

Reported herein is a novel ultrarobust and biomimetic hierarchically macroporous ceramic membrane that can achieve a high efficiency of up to 99.98% for oil−water separation, while the efficiency remains nearly unchanged even after 10 rounds of use and storage for up to 4 months. The macroporous ceramic membrane is prepared by combining surface hydrophobic coating with an emulsion-assisted template selfassembly of the modified Al 2 O 3 ceramic powder. The as-prepared ceramic membrane is a lightweight material with high strength because the relative density is only ∼1.02 g/cm 3 ; the compressive strength of the as-prepared ceramic membrane is expected to be 15-fold higher than that of the sample prepared using the traditional solid template approach even at a higher porosity due to the principle of self-assembly of Al 2 O 3 particles. It is the mechanism of self-assembly that has broken the traditional principle in ceramic preparation that leads to a perfectly dense packing structure. Moreover, the ceramic membrane maintained excellent oil− water separation efficiency, because of which even after its top layer was damaged by sand impingement, superfine particles could be separated using our macroporous membrane due to the featured interconnected pore structure. We anticipate that this example of the combination of a superwettability theory and a traditional ceramic material can provide an important application direction of advanced oil−water separation techniques.

Novel Strategy To Prepare Hierarchically Porous Ceramic Microspheres via a Self-Assembly Method on Tunable Superamphiphobic Surfaces

“…Recently, the construction of lightweight and high-strength Al 2 O 3 porous ceramics by utilizing emulsified oil as the sacrificial template has been reported. 13 The as-prepared Al 2 O 3 ceramic suspension has a very low viscosity owing to the addition of the oil phase in the system. Therefore, we choose such an emulsion self-assembly approach to fabricate the hierarchically porous ceramic microspheres by combination with the superwettability strategy.…”

“…The experimental procedures are described in the Supporting Information. The ceramic suspension was prepared as follows (Figure 1a): 13 first of all, the Al 2 O 3 aqueous colloidal suspension was sonicated and acidized (pH < 5) by adding HCl. Followed by ball milling of the Al 2 O 3 suspension for a whole night, propionic acid, as the surface modifier, was then added dropwise into the suspension under vigorous stirring.…”

“…In such a case, the modified Al 2 O 3 with amphipathicity and PVA with partial hydrophobicity after hydrolysis would competitively self-assemble around the oil droplet and then adsorb on the air/oil−water interface to form an attractive percolating network between the droplets. 13 Interestingly, we discovered that the as-prepared ceramic suspension is highly pH-sensitive, that is, the viscosity can be greatly changed by adding an acid or alkali solution. As shown in Figure 1b,c illustrated in Figure 2a.…”

Hydrophobically modified melamine‐formaldehyde sponge used for conformance control and water shutoff during oil production

“…In recent years, some newly developed hydrophobic materials have been used for oilwater separation due to the special selectivity toward oil and water. Many materials such as metal meshes, 16 membranes, 17 sponges, 18 and fabrics 19 can be modified into highly hydrophobic or super-hydrophobic as matrix materials to separate oil and water. For example, Liu et al 20 fabricated a durable super-hydrophobic stainlesssteel mesh using a facile solution immersion method.…”

Development of Red Clay Ultrafiltration Membranes for Oil-Water Separation

“…The fabricated membrane had a pore diameter of 1.2 µm and showed 99% oil separation at a flow rate of 85 L/m 2 •h and pressure of 50 kPa. A porous MF aluminum ceramic membrane was applied by Liu et al for oil-water separation [10]; they reported 99.98% removal of emulsified oil.…”